roadmaster rear 8.5"?

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bfurches

Posts : 1061Join date : 2010-04-20Age : 30Location : Springfield, MA

Subject: roadmaster rear 8.5"? Tue Aug 10, 2010 3:25 pm

So at my buddys junk yard, he has a 96 roadmaster lt1 sedan. He has no keys so I cant get in the trunk to check the rpo codes, but generally, what did these come with for gear sets and were they posi units if they had lt1s?

Also, its the 8.5" ring gear right? (i didnt have time to jack it up and look at the rear cover, so I cant tell until tomorow).

It has the rear sway bar, but thats all i really noticed. I didnt even check if it hyas disc, but the price is right so I am gunna pull it tomorow.

bammax

Posts : 2301Join date : 2009-02-22Age : 36Location : Mansfield, Ma

Subject: Re: roadmaster rear 8.5"? Tue Aug 10, 2010 3:52 pm

All Roadies had the LT1. All wagons did too.

Now for the specs I'm a bit hazy. If I remember the SS and 9c1's are the cars that had disks and the rest got 9" or 11" drums. Same for the posi with the SS and 9c1 getting it while the rest typically didn't. The gearing is generally going to be in the neighborhood of 2.93:1

Without checking codes or taking things apart I'd assume it has 2.93 with 11" drums and non-posi. It may have more to it, but don't pay for something based on what it may have

Sedan housings, in both widths, have the same lower control arm bracket location/spread distance, and will fit any other sedan frame. Wagons have a wider spread distance (approx. 2") between lower control arm brackets on housing, and corresponding wider frame lower control arm mounts.---------------------------------------------------------------------------------------------Parts listed are applicable to 94-96 B-body sedans, some may be applicable to 91-93 models.

Note: information posted is as found on manufacturer/supplier websites. There ARE errors--some listings show NARROW housing axles as fitting Impala SS, which is incorrect--as relates to PRODUCTION configuration.

Stock '94-96 Caprice and Roadmaster sedans and wagons came with 2.56 gears as a base and 2.93 gears were an option.

Stock '94-96 Caprice 9C1s and Impala SS's came with 3.08.

Limited slip differential option (code G80 on the Service Parts ID sticker (SPID)) is an Auburn oem-style differential that is non-rebuildable. Aftermarket Auburn differentials are rebuildable by Auburn through an exchange program. The differential is an 8.5" style with 30-spline axles.

So at my buddys junk yard, he has a 96 roadmaster lt1 sedan. He has no keys so I cant get in the trunk to check the rpo codes, but generally, what did these come with for gear sets and were they posi units if they had lt1s?

Also, its the 8.5" ring gear right? (i didnt have time to jack it up and look at the rear cover, so I cant tell until tomorow).

It has the rear sway bar, but thats all i really noticed. I didnt even check if it hyas disc, but the price is right so I am gunna pull it tomorow.

My 96 RMS Limited has a 2.56 RATIO with a G80....this is a non tow pack FE1 softride...if this info at all helps lol

Deputy347K9

Posts : 147Join date : 2009-04-05Location : Limington, Maine

Subject: Re: roadmaster rear 8.5"? Tue Aug 10, 2010 4:53 pm

Not sure if your looking for a set of gears from a Roadmaster or not, however, I do have a nice posi Auburn unit 2:56 gears out of a 95 Roadmaster. Just under 70K on them when replaced with an Easton posi unit with 4:11s. Not even sure of the value.

Larry

Cadet57

Posts : 4481Join date : 2010-03-14Age : 30Location : Chicopee, MA

Subject: Re: roadmaster rear 8.5"? Tue Aug 10, 2010 5:03 pm

bfurches wrote:

So at my buddys junk yard, he has a 96 roadmaster lt1 sedan. He has no keys so I cant get in the trunk to check the rpo codes, but generally, what did these come with for gear sets and were they posi units if they had lt1s?

Also, its the 8.5" ring gear right? (i didnt have time to jack it up and look at the rear cover, so I cant tell until tomorow).

It has the rear sway bar, but thats all i really noticed. I didnt even check if it hyas disc, but the price is right so I am gunna pull it tomorow.

Is that the green limited Roadmaster at Center? If not, where is this car and how is the interior?

GuestGuest

Subject: Re: roadmaster rear 8.5"? Tue Aug 10, 2010 5:15 pm

If it has 2.56 gears it is a 7.5 housing. If 2.93 it would be a 8.5

Cadet57

Posts : 4481Join date : 2010-03-14Age : 30Location : Chicopee, MA

Subject: Re: roadmaster rear 8.5"? Tue Aug 10, 2010 5:22 pm

IMPALADAKID wrote:

If it has 2.56 gears it is a 7.5 housing. If 2.93 it would be a 8.5

3.23's have an 8.5 too right? At least thats what my FSM says for my car...

GuestGuest

Subject: Re: roadmaster rear 8.5"? Tue Aug 10, 2010 5:28 pm

Cadet57 wrote:

IMPALADAKID wrote:

If it has 2.56 gears it is a 7.5 housing. If 2.93 it would be a 8.5

3.23's have an 8.5 too right? At least thats what my FSM says for my car...

Yup.

Cadet57

Posts : 4481Join date : 2010-03-14Age : 30Location : Chicopee, MA

Subject: Re: roadmaster rear 8.5"? Tue Aug 10, 2010 5:33 pm

IMPALADAKID wrote:

Cadet57 wrote:

IMPALADAKID wrote:

If it has 2.56 gears it is a 7.5 housing. If 2.93 it would be a 8.5

3.23's have an 8.5 too right? At least thats what my FSM says for my car...

Yup.

Now I hate to derail a thread with my own rambling.... Which is why I am going to

Can someone teach the noobie the difference between the different gear ratios and their different uses? IE, why do I have 3.23's in my car?

GuestGuest

Subject: Re: roadmaster rear 8.5"? Tue Aug 10, 2010 6:06 pm

Cadet57 wrote:

IMPALADAKID wrote:

Cadet57 wrote:

IMPALADAKID wrote:

If it has 2.56 gears it is a 7.5 housing. If 2.93 it would be a 8.5

3.23's have an 8.5 too right? At least thats what my FSM says for my car...

Yup.

Now I hate to derail a thread with my own rambling.... Which is why I am going to

Can someone teach the noobie the difference between the different gear ratios and their different uses? IE, why do I have 3.23's in my car?

Less torque requires more gear, as does tow package. Your car is a 305, and needs more gear to get it going.

Cadet57

Posts : 4481Join date : 2010-03-14Age : 30Location : Chicopee, MA

Subject: Re: roadmaster rear 8.5"? Tue Aug 10, 2010 6:10 pm

IMPALADAKID wrote:

Cadet57 wrote:

IMPALADAKID wrote:

Cadet57 wrote:

IMPALADAKID wrote:

If it has 2.56 gears it is a 7.5 housing. If 2.93 it would be a 8.5

3.23's have an 8.5 too right? At least thats what my FSM says for my car...

Yup.

Now I hate to derail a thread with my own rambling.... Which is why I am going to

Can someone teach the noobie the difference between the different gear ratios and their different uses? IE, why do I have 3.23's in my car?

Less torque requires more gear, as does tow package. Your car is a 305, and needs more gear to get it going.

Actually, mine's a 350. It has the GU5 3.23, and a G80 posi plus G67 springs. I dunno if the guy just kept checking all the boxes at the dealer or what lol.

Matt Trakker

Posts : 5087Join date : 2009-07-30Age : 36Location : Reading, MA

Subject: Re: roadmaster rear 8.5"? Tue Aug 10, 2010 9:01 pm

My Caprice has the wide rear axle, but I guess it's a 7.5? It's a 2.56 open, but the car is a 305.

My brothers '94 RMS is the 2.56 G80, but it has a trailer tow package on it, which is strange.

GuestGuest

Subject: Re: roadmaster rear 8.5"? Tue Aug 10, 2010 9:06 pm

Matt Trakker wrote:

My Caprice has the wide rear axle, but I guess it's a 7.5? It's a 2.56 open, but the car is a 305.

My brothers '94 RMS is the 2.56 G80, but it has a trailer tow package on it, which is strange.

That is wierd. The posi was optional with all but the Impala, and not available with the fleetwood, but the 2.93 is the standard gear with the tow package.

Matt Trakker

Posts : 5087Join date : 2009-07-30Age : 36Location : Reading, MA

Subject: Re: roadmaster rear 8.5"? Tue Aug 10, 2010 9:11 pm

IMPALADAKID wrote:

Matt Trakker wrote:

My Caprice has the wide rear axle, but I guess it's a 7.5? It's a 2.56 open, but the car is a 305.

My brothers '94 RMS is the 2.56 G80, but it has a trailer tow package on it, which is strange.

That is wierd. The posi was optional with all but the Impala, and not available with the fleetwood, but the 2.93 is the standard gear with the tow package.

The car has a lot of random options. "Supposedly", the guy who originally owned it worked for GM and special ordered it with a bunch of things, then somehow oversaw them building the car, I don't know how true that is though. According to that VIN decoder site it was one of two built just like it, lol.

bfurches

Posts : 1061Join date : 2010-04-20Age : 30Location : Springfield, MA

Subject: Re: roadmaster rear 8.5"? Tue Aug 10, 2010 10:05 pm

I suppose I will find out tomorow morning lol.

Yea justin, its the greenish blue one up at center. They have two more parked next to it. I think I am going to grab the plastic fuel tank out of her too (still fills behind the license plate just like my boxy

bfurches

Posts : 1061Join date : 2010-04-20Age : 30Location : Springfield, MA

Subject: Re: roadmaster rear 8.5"? Wed Aug 11, 2010 6:04 pm

Well, i lucked out. The rear was an 8.5 posi with 2.93 gears, 11 drums, and included sway bar and wheels/ tires for 150.Had 110k on the clock.

Cadet57

Posts : 4481Join date : 2010-03-14Age : 30Location : Chicopee, MA

Subject: Re: roadmaster rear 8.5"? Wed Aug 11, 2010 6:30 pm

bfurches wrote:

Well, i lucked out. The rear was an 8.5 posi with 2.93 gears, 11 drums, and included sway bar and wheels/ tires for 150.Had 110k on the clock.

Hmmm. Any of them have good interiors? Hopefully gray... I've been itching for some RM seats.

bammax

Posts : 2301Join date : 2009-02-22Age : 36Location : Mansfield, Ma

Subject: Re: roadmaster rear 8.5"? Wed Aug 11, 2010 7:58 pm

bfurches wrote:

Well, i lucked out. The rear was an 8.5 posi with 2.93 gears, 11 drums, and included sway bar and wheels/ tires for 150.Had 110k on the clock.

That's a good deal. If I could find a deal half as good as that I'd jump on it for my car. Seems all I find are rotten housings for $300 bucks

bfurches

Posts : 1061Join date : 2010-04-20Age : 30Location : Springfield, MA

Subject: Re: roadmaster rear 8.5"? Wed Aug 11, 2010 10:51 pm

taking a break from the swap and waiting for my other set of hands to get here, but here are some pics...

...new rear all cleaned up and quick paint. I pulled the cover and checked the carrier and gears, put a newer cover/ hardware on it, replaced the fluid and swapped my stainless braided lines over.

Old housing ripped out and ready for a make-over. Im going to strip the housing tomorrow and send it out to have the tubes welded and the housing powder coated. The ends weren't as bad as I thought, just the bearing...So i will use the roadie housing temporarily while I build this one...

damage from the axle snapping. Notice the half dollar size holes in the wheel well

...its gunna suck for now with these 2.93's....but at least its only temporary...